Five pupils and a police officer were injured during a protest over a disputed piece of land at Langa'ta Road Primary School in Nairobi on Monday.
The protest, publicised on social media as #OccupyPlayGround, resulted in a wall that was built around the land by a developer being brought down.
Separately, the Lands Cabinet Secretary and the National Land Commission chairman promised the land would be returned to the school.
Police threw tear gas canisters at the pupils and other demonstrators who had joined them to protest the alleged grabbing of the school's playground.
Some of the pupils were injured in a stampede after the police cornered them between the road and the wall. They were attempting to enter via the gate, which had been reinforced with stones from the inside.
The police, in full riot gear, also had five dogs. They were at the school from 6am.
The protest came after the expiry of a notice given by Kibra MP Kenneth Okoth, who threatened to mobilise youths from the constituency to pull down a wall erected by a developer.